A differential neural response to threatening and non-threatening negativefacial expressions in paranoid and non-paranoid schizophrenics

Several studies have demonstrated impaired facial expression recognition in schizophrenia. Few have examined the neural basis for this; none have comp ared the neural correlates of facial expression perception in different sch izophrenic patient subgroups. We compared neural responses to facial expres sions in 10 right-handed schizophrenic patients (five paranoid and five non -paranoid) and five normal volunteers using functional Magnetic Resonance I maging (fMRI). In three 5-min experiments, subjects viewed alternating 30-s blocks of black-and-white facial expressions of either fear, anger or disg ust contrasted with expressions of mild happiness. After scanning, subjects categorised each expression. All patients were less accurate in identifyin g expressions, and showed less activation to these stimuli than normals. No n-paranoids performed poorly in the identification task and failed to activ ate neural regions that are normally linked with perception of these stimul i. They categorised disgust as either anger or fear more frequently than pa ranoids, and demonstrated in response to disgust expressions activation in the amygdala, a region associated with perception of fearful faces. Paranoi ds were more accurate in recognising expressions, and demonstrated greater activation than non-paranoids to most stimuli. We provide the first evidenc e for a distinction between two schizophrenic patient subgroups on the basi s of recognition of and neural response to different negative facial expres sions. (C) 1999 Elsevier Science Ireland Ltd. All rights reserved.